CHAPTER 4 - ELECTRICAL SYSTEM

A motor vehicle's electrical system consists of electrical and electronic components ensure the power supply, control and operation of the vehicle's various systems and equipment​.

This system plays an important role in the motor vehicle's operation, safety and comfort, as it serves systems such as engine starting, lighting, signalling, ignition, measuring and monitoring instruments, and various auxiliary equipment.

Typically, the motor vehicle's electrical system uses a wire to supply power to electrical loads, usually the positive (+) wire, while the motor vehicle's metal structure serves as the negative (-) return conductor to complete the circuit. In most motor vehicles, the nominal voltage of the electrical system is 12 V.

In some motor vehicles, such as lorries, buses or other large vehicles, the electrical system may operate at 24 V. In addition, some modern motor vehicles may have auxiliary 48 V electrical systems, while hybrid and electric vehicles also use high-voltage circuits for the electric propulsion system.

The electrical distribution system consists of the key-operated ignition switch or starting system, wires, on/off switches, selector switches, connectors, fuses or circuit breakers, relays and electrical sockets.

The motor vehicle's main electrical loads are the ignition system, starting system, lighting system, visual and audible signalling system, measuring and monitoring instruments, and auxiliary equipment.

The lighting system illuminates public roads, particularly at night or in conditions of reduced visibility. In addition, it helps other road users see the motor vehicle.

Motor vehicle lighting can be:

• interior, consisting of instrument panel lights, roof-mounted interior lights and other light sources in the passenger compartment;
• exterior, which allows the driver to see the road, obstacles and other road users, while also making the motor vehicle visible to them.

The exterior lighting equipment mainly consists of headlights, direction indicator lamps, front and rear position lamps, rear fog lamps, front fog lamps (if fitted), a reversing lamp and number plate lamps.

The motor vehicle's dashboard comprises the instruments, warning lights, controls and gauges located within the driver's field of view. It displays information about the motor vehicle's operation, as well as any faults or warnings.

The on-board computer is an electronic system that collects, processes and displays information received from various motor vehicle systems. It provides the driver with information about the vehicle's operation and can indicate certain errors, warnings or faults that arise during use.